Research On WSN Routing Algorithm Along Railway Lines Based On Energy Harvesting

With the rapid development of high-speed railways in China,the safety and stability of the train operating environment has been put forward higher requirements.At present,the data transmission of train operation environment monitoring system still based on the wired network,which raise the cost and difficulty of construction and maintenance.And it is not conducive to large-scale deployment along the railway and real-time monitoring of the harsh environment.The wireless sensor network(WSN)has the characteristics of wide coverage area,self-organization,low power consumption,high detection accuracy,wireless and so on.WSN can not only achieve the real-time monitoring of all physical quantities required in the coverage area along railway lines,but also reduce the construction cost and the maintenance difficulty,thereby WSN is quite suitable for data monitoring application of the train operating environment monitoring system.But,traditional WSN nodes are powered by batteries.And the limitation of battery capacity has become an important reason that restricting the development of WSN.Therefore,the energy harvesting WSN,in which nodes can powered by energy harvesting form ambience,and effectively alleviates the contradiction between node energy saving and network performance improvement.In this dissertation,the WSN routing algorithm along railway lines is studied.Based on the energy harvesting WSN and linear WSN,a WSN routing algorithm along railway lines based on solar energy harvesting is proposed.The simulation analysis proves the superiority of the proposed algorithm.The main work and research results of the dissertation are as follows:(1)Research on energy harvesting WSN and linear WSN.In-depth analysis of the characteristics and typical routing algorithms of energy harvesting WSN and linear WSN.The analysis shows that: energy harvesting WSN can effectively extend the network life cycle and improve network performance.And linear WSN can quite suitable for the monitoring application of linear areas such as pipelines,mines,railways and so on.However,the main problems currently exist are: linear topology makes nodes more prone to "energy holes" problem,which caused by unbalance of node energy consumption.The other problem is that the collected energy cannot be managed and utilized efficiently.(2)Research on WSN routing algorithm along railway lines based on energy harvesting.By analyzing the network requirements and network architecture of WSN along railway lines,a uniform deployment method for WSN nodes is established.According to the problem of “energy holes” easily generated by linear WSN,the node energy harvesting model with solar energy harvesting function is constructed,and combined with the energy consumption of nodes in the process of information transmission,an energy efficient routing algorithm based on uniform node clustering is proposed.According to the problem that the collected energy cannot be efficiently managed and utilized,considering that the solar energy harvesting has certain randomness,time-varying and fluctuates greatly under the influence of weather,this dissertation discusses the variation trend of node energy harvesting power in sunny and cloudy weather respectively.Divide the network into four states,and set different transmission thresholds for different states.(3)Using the simulation software of MATLAB to simulate the proposed routing algorithm.Firstly,the uniform clustering and multi-hop routing algorithm proposed in this dissertation is compared with single-hop data transmission by simulation.The simulation results show that the proposed routing algorithm has a longer life cycle than single-hop transmission and the node energy consumption is more balanced.Then discuss the impact of the different number of nodes in clusters on the network life cycle and network energy consumption,so as to determine the optimal number of nodes in the cluster for the subsequent simulation experiments.Finally,the influences of different threshold values on the network life cycle,network residual energy,and number of data packet transmissions is analyzed under sunny and cloudy conditions.According to the remaining energy of the network at sunset,the maximum value of the transmission threshold when no energy harvesting at night can be determined.The simulation results show that the proposed routing algorithm can effectively balance the energy consumption between nodes and extend the network life cycle.